[Definition, primary examination and differential diagnostics in acute dyspnea].

The topic of acute dyspnea is presented in two separate articles. This first part deals with the definition and pathophysiology of dyspnea as well as important considerations on the history of the present illness, physical examination, initial therapy and differential diagnostic considerations. The second part covers relevant diagnostic investigations and principles for the initial management. The causes, consequences and perception of acute dyspnea can be very different. The adult patient with acute dyspnea presents difficult challenges in the diagnosis and management. The emergency clinician must work through a wide range of differential diagnostic considerations while providing appropriate initial treatment for a potentially life-threatening disease.